Effect of Pd addition in ENIG surface finish on drop reliability of Sn-Ag-Cu solder joint

Abstract

The reliability of lead-free electronic assemblies after board-level drop tests was investigated. The effects of different PCB (Printed Circuit Board) surface finishes, viz. ENIG (Electroless Nickel Immersion Gold) and ENEPIG (Electroless Nickel Electroless Palladium Immersion Gold), after reflow and thermal aging (1,000 h at 125°C) were studied. The increase of IMCs (Intermetallic Compounds) thickness after thermal aging in all of boards. However, as the change of the thickness of the IMC in the ENEPIG board before and after thermal aging was smaller than that of the ENIG board. The results of the drop test, ENEPIG board has greater reliability after reflow than the ENIG board and shows excellent characteristics under all conditions after thermal aging. © 2011 The Japan Institute of Metals.